1. Field of the Invention
The present invention relates to a thermoelectric generator of vehicle, and more particularly, to a thermoelectric generator of vehicle, which uses the heat of the exhaust gas of an automobile to generate electricity.
2. Description of Related Art
A thermoelectric element is an element, which uses a thermoelectric phenomenon, in which thermal energy is converted to electric energy by converting the temperature gap between the two ends of an element into electricity, or in which electric energy is converted to thermal energy by having electricity run through an element and by causing the temperature gap in the two ends. Such thermoelectric element is used in a small scale cooling, heating or generating device.
When a thermoelectric element is used in a small scale generating device, it is called a thermoelectric generation device or a thermoelectric generator. This device is mainly used in a power supply unit of a wireless communication device, of a spaceship and of a nuclear-powered submarine as well as in a thermoelectric generator installed in an exhaust system of a vehicle.
FIG. 1 is a cross-sectional view illustrating a thermoelectric generator of a vehicle.
As illustrated, a thermoelectric generator installed in an exhaust system of a vehicle 10 comprises; a hexagonal exhaust heat recovering device 40, which high-temperature exhaust gas passes through; a cooling device 30, which is installed outside of the exhaust heat recovering device 40 and inside of which coolant passes through; and the multitude of thermoelectric modules 20, which are in contact with the exterior of the exhaust heat recovering device 40 and with the interior of the cooling device 30 to generate electricity using the temperature gap between the two ends.
Inside the exhaust heat recovering device 40, high-temperature exhaust gas runs and it conveys thermal energy to the thermoelectric modules 20. Inside the cooling device 30 is formed a cooling pipe, which increases the temperature gap between the interior of the thermoelectric modules 20 in contact with the exhaust heat recovering device 40 and the exterior of the thermoelectric modules 20 in contact with the cooling device 30. As the temperature gap between the interior and the exterior of the thermoelectric module increases 20, the efficiency of the thermoelectric generator installed in the exhaust system of a vehicle increases.
In order to generate lots of electricity in a thermoelectric generator, i.e. to increase the thermoelectric generation efficiency, thermal energy of the exhaust gas must be conveyed to the thermoelectric modules efficiently. However, in the traditional thermoelectric generator of a vehicle, thermal energy of the exhaust gas is not conveyed to the high temperature member sufficiently, so the recovery rate of the thermal energy of the exhaust gas drops and hence, the thermoelectric efficiency of a thermoelectric generator drops.
Also, in the traditional thermoelectric generator of a vehicle, although a cooling device 30 occupies a great area, the heat-exchange area is small, and therefore, the heat conveyance rate is low compared to the size, and the efficiency of thermoelectric generation is low.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.